1. Technical Field
Embodiments of the present invention relate to components used to test integrated circuit devices under test (DUTs), either on a wafer, or diced up into individual dies. More particularly, embodiments of the present invention relate to test probes used to electrically connect a test system to electrical contact pads of the DUTs.
2. Related Art
Test systems to test DUTs during fabrication of a wafer typically include a test system controller that applies signals through channels of a probe card supporting test probes. The test probes are typically resilient to reduce damage to the wafer and the probes themselves during testing. To perform testing, the probes are brought into contact with conductive bond pads of DUTs formed on the wafer. In some cases, similar testing can be performed with a test system and probe card to test dies after the dies have been cut out from the wafer, but before wires are bonded to bond pads of DUTs on the dies.
During testing, contact made between the bond pads and resilient probes of the test system can cause damage to the DUT being fabricated. Contact between the probes and bond pads cause a scrub, or mark to be created on the bond pads being fabricated. Further, with a scrub made on the bond pad, debris will be created that must be cleaned from both the wafer and the probe card after testing.
Test systems have been proposed that enable testing without contact with pads of a DUT by moving a probe card close to a DUT without the probes touching, leaving an air gap. One such system is described in U.S. Pat. No. 6,882,239 by Miller, entitled “Electromagnetically Coupled Interconnect System.” Another such system is described in U.S. Pat. No. 6,600,325 by Coates, et al., entitled “Method And Apparatus For Probing An Integrated Circuit Through Capacitive Coupling.” It is desirable to provide further test systems that offer has less potential for scrubbing or damaging DUTs on a wafer or die during testing, and to decrease the amount of debris created due to scrubs of bond pads by test probes during testing.